Index: kernel/generic/src/ipc/sysipc.c
===================================================================
--- kernel/generic/src/ipc/sysipc.c	(revision 34aac916e2dbd00d27c9af667c75137a0bac43a1)
+++ kernel/generic/src/ipc/sysipc.c	(revision 75ebb5b6271b6a2c74a51ea695d73085ed9b97db)
@@ -60,8 +60,8 @@
 #define GET_CHECK_PHONE(phone, phoneid, err) \
 { \
-	if (phoneid >= IPC_MAX_PHONES) { \
+	if ((unative_t) (phoneid) >= IPC_MAX_PHONES) { \
 		err \
 	} \
-	phone = &TASK->phones[phoneid]; \
+	phone = &TASK->phones[(phoneid)]; \
 }